Communication device, communication method, and program

Abstract

This invention provides a data communication method for a communication device capable of communicating using a communication link composed of multiple channels. [Solution] The method is configured to enable communication by bonding a first channel and a second channel different from the first channel, and communicates using a plurality of communication methods, including a first communication method that acquires transmission rights and communicates using the first channel, and a second communication method that acquires transmission rights and communicates using the second channel when the first channel cannot be used, and when a received frame received on the first channel is a wireless frame communicated at a specified OBSS, communication is performed using the second communication method, and based on the fact that the received frame was transmitted from a non-access point station other than an access point, communication is performed using the first communication method without using the second communication method.

Description

Technical Field

[0001] The present invention relates to data communication technology in a communication device capable of communicating using a communication link composed of a plurality of channels.

Background Art

[0002] In recent years, with the increase in the amount of data to be communicated, the development of communication technologies such as wireless LAN (Local Area Network) has been promoted. As the main communication standards for wireless LAN, the IEEE (Institute of Electrical and Electronic Engineers) 802.11 standard series is known. The IEEE 802.11 standard series includes IEEE 802.11a / b / g / n / ac / ax / be standards, etc. For further improvement of communication reliability, the development of the IEEE 802.11bn standard is in progress as a successor standard to the IEEE 802.11be standard.

[0003] As one of the candidate technologies included in the IEEE 802.11bn standard, a technology for efficiently using frequency resources in a communication method using a communication link composed of a plurality of channels has been studied. For example, in Patent Document 1, when the Primary Channel used when a communication device acquires a transmission right cannot be used due to some factor, a technology for temporarily acquiring the transmission right using a non-primary channel and performing communication is described.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] This invention provides a technology that enables efficient use of frequency resources in a communication system that uses a communication link composed of multiple channels. [Means for solving the problem]

[0006] A communication device according to one aspect of the present invention is a communication device that communicates with other communication devices using wireless frames compliant with the IEEE 802.11 standard series, and comprises a first communication method configured to enable communication by bonding a first channel and a second channel different from the first channel, and includes a first communication method that acquires transmission rights and performs communication using the first channel, and a second communication method that acquires transmission rights and performs communication using the second channel when the first channel cannot be used, and communication means that performs communication using a plurality of communication methods, and an access point different from the communication device and the other communication device, configured as Overlapping Basic Service A Set(OBSS) includes a identifying means for identifying an OBSS in which the radio frame transmitted by the access point is received by both the communication device and the other communication device on the first channel, wherein the communication means, after the identification, if the received frame received on the first channel is the radio frame communicated in the identified OBSS, communicates using the second communication method based on the fact that the received frame was transmitted from the access point, and communicates using the first communication method without using the second communication method based on the fact that the received frame was transmitted from a non-access point station other than the access point. [Effects of the Invention]

[0007] According to the present invention, frequency resources can be used efficiently in a communication system that uses a communication link composed of multiple channels. [Brief explanation of the drawing]

[0008] [Figure 1]This is a diagram showing an example configuration of a wireless communication system. [Figure 2] This is a schematic diagram showing an example of a time chart for data transmission by a communication device. [Figure 3] This figure shows an example of the hardware configuration of a communication device. [Figure 4] This figure shows an example of the functional configuration of a communication device. [Figure 5] This figure shows an example sequence of events performed between AP and STA. [Figure 6] This figure shows an example of the HE PPDU configuration. [Figure 7] This figure shows an example of a UHR PPDU configuration. [Figure 8] This figure shows an example of MAC frame structure. [Figure 9] This figure shows an example of the configuration of a trigger frame. [Figure 10] This diagram shows an example of the processing flow performed when a communication device transmits data. [Modes for carrying out the invention]

[0009] The embodiments will be described in detail below with reference to the attached drawings. Note that the following embodiments do not limit the invention as defined in the claims. While the embodiments describe multiple features, not all of these features are essential to the invention, and the features may be combined in any way. Furthermore, in the attached drawings, identical or similar configurations are given the same reference numerals, and redundant descriptions are omitted.

[0010] (System Configuration) Figure 1 shows an example configuration of a wireless communication system according to this embodiment. The wireless communication system includes, for example, an access point (AP) 101, stations (STAs) 111 and STA112. AP101, STA111, and STA112 are communication devices capable of performing wireless communication compliant with the IEEE 802.11 standard series. IEEE is an abbreviation for Institute of Electrical and Electronics Engineers. Figure 1 shows a configuration in which STA111 and STA112 participate in a network 121 formed by AP101. Network 121 may also be called a Basic Service Set (BSS). In Figure 1, a configuration is shown in which one AP and two STAs exist in network 121, but for example, there may be multiple APs, and there may be one or more STAs. Also, in that case, each STA may be connected to one AP, or one STA may be connected to multiple APs. In Figure 1, near network 121, there are two networks: network 122, composed of AP102 and STA113, and network 123, composed of AP103 and STA114. AP102, AP103, STA113, and STA114 are communication devices capable of performing wireless communication compliant with the IEEE 802.11 standard series, similar to AP101, STA111, and STA112. For AP101, STA111, and STA112, network 121 is the BSS to which their devices connect, and can be called their own BSS. On the other hand, for AP101, STA111, and STA112, networks 122 and 123 are networks that can interfere with their own BSS, and can be called Overlapping BSS (OBSS). The following explanation will focus on AP101, STA111, and STA112, but the same explanation can also be applied to AP102, AP103, STA113, and STA114. In this embodiment, STA111 and STA112 may be referred to as STA110 without distinction. Also, AP101, STA111, and STA112 may be collectively referred to as communication device 100.

[0011] In this embodiment, the communication device 100 is configured to execute a communication method compliant with the IEEE 802.11bn standard. The IEEE 802.11bn standard is the successor to the IEEE 802.11be standard, which aims for a maximum transmission speed of 46.08 Gbps (Gigabit per second). The main features of the IEEE 802.11bn standard are that it has functions that realize highly reliable communication, low latency communication, and improved throughput when communication traffic is congested. The wireless frame used in the communication method compliant with this standard may be called UHR (Ultra High Reliability) PPDU. PPDU is an abbreviation for PLCP Protocol Data Unit, and PLCP is an abbreviation for Physical Layer Convergence Protocol. Note that the names UHR and IEEE 802.11bn may be changed to other names when the development of this standard is completed. Furthermore, it should be noted that this specification and the claims attached herein are applicable to communication devices using any successor standard to IEEE 802.11be. A successor standard to IEEE 802.11be may be a standard released after the release of the IEEE 802.11be standard. Also, the communication device 100 may support at least one of the legacy standards prior to the IEEE 802.11bn standard. Legacy standards include, for example, the IEEE 802.11a / b / g / n / ac / ax / be standards. The communication device 100 may also support other communication standards such as Bluetooth®, Bluetooth LE (Low Energy), NFC, UWB, ZigBee, and MBOA. UWB is an abbreviation for Ultra Wide Band, and MBOA is an abbreviation for Multi Band OFDM Alliance. NFC is an abbreviation for Near Field Communication. UWB includes wireless USB, wireless 1394, WiNET, etc. Furthermore, the communication device 100 may support communication standards such as wired LANs using Ethernet cables or optical fibers.The communication device 100 may support cellular communication standards such as 5G and LTE as defined by the Third Generation Partnership Project (3GPP). LTE is an abbreviation for Long Term Evolution. AP101 is, for example, a wireless LAN router or a personal computer (PC), but is not limited to these. AP101 may be an information processing device such as a wireless chip capable of performing wireless communication compliant with the IEEE 802.11bn standard. STA110 is, for example, a camera, tablet, smartphone, PC, mobile phone, video camera, headset, smart glasses, HMD (head-mounted display), or other wearable device, but is not limited to these. STA110 may be an information processing device such as a wireless chip capable of performing wireless communication that supports the transmission and reception of PPDU compliant with the IEEE 802.11bn standard. In this case, the wireless chip can be configured to perform various controls by hardware circuits inside the wireless chip. It can also be configured so that various processes are performed by the cooperation of a processor such as ASIP, memory, and hardware circuits inside the wireless chip. ASIP is an abbreviation for Application-specific instruction set processor.

[0012] The communication device 100 can communicate using radio signals in frequency bands such as the 2.4GHz, 3.6GHz, 5GHz, 6GHz bands, and millimeter wave bands such as the 45GHz and 60GHz bands. The frequency bands used by the communication device 100 are not limited to these, and may include, for example, the Sub1GHz band. Furthermore, the communication device 100 can communicate using bandwidths of 20MHz, 40MHz, 80MHz, 160MHz, 320MHz, 540MHz, 640MHz, 1080MHz, and 2160MHz. The bandwidths used by the communication device 100 are not limited to these, and may include, for example, 240MHz or 4MHz. Note that the IEEE 802.11 standard series specifies frequency channels using a 20MHz bandwidth as basic channels in frequency bands such as the 2.4GHz, 5GHz, and 6GHz bands. In addition, this standard defines multiple usable channels in each of the 2.4GHz, 5GHz, and 6GHz frequency bands. In this standard, the communication device 100 may use one channel in combination with other adjacent channels. This use of one channel in combination with other adjacent channels may be called channel bonding. A bundle of channels formed by one or two or more adjacent channels may be called a communication link. That is, one link formed by two channels with a bandwidth of 20 MHz may use a bandwidth of 40 MHz. The IEEE 802.11be standard is expected to specify 320 MHz as the maximum bandwidth available for a single link. Signals transmitted in this bandwidth may be continuous or discontinuous on the frequency axis. AP101 and STA110 may be AP MLDs (Multi-Link Devices) and STA MLDs, respectively, that support Multi-Link, enabling communication by establishing multiple links simultaneously.

[0013] When the communication device 100 transmits a signal using a link established with another communication device, it performs carrier sensing to determine whether or not to transmit. Carrier sensing is the operation in which the communication device 100 determines whether or not there is a signal on the channel that it intends to use for transmission. For example, the communication device 100 measures the strength of the signal received on the channel (received signal strength) and determines that a signal exists if the received signal strength exceeds a predetermined threshold (physical carrier sensing). The received signal strength may also be called the Received Signal Strength Indicator (RSSI). The communication device 100 may also determine the presence or absence of a signal based on information such as the Duration field contained in the signal received on the channel (virtual carrier sensing). For example, the communication device 100 stores the period indicated by the Duration field contained in the received signal as a Network Allocation Vector (NAV) within itself. The communication device 100 can treat the stored NAV as a period during which it does not transmit. In this embodiment, the operation by which the communication device 100 sets a period during which it will not transmit based on information such as the Duration field of the received signal is called setting NAV. That is, until the NAV set for the channel expires, the communication device 100 determines that a signal is present on the channel. In this way, the communication device 100 determines whether or not a signal is present on the channel based on the results of performing physical carrier sensing and virtual carrier sensing. If the communication device 100 determines that a signal is present on the channel, it may determine that transmission is not possible. In this case, the state of the channel may be called a busy state. On the other hand, a state in which no signal is detected on the channel in carrier sensing and NAV is not set may be called an idle state. If the channel is in an idle state, the communication device 100 may determine that transmission is possible.

[0014] The communication device 100, for example, when communicating using a 160MHz bandwidth link, can determine whether transmission is possible using only the 20MHz bandwidth Primary Channel (PCH) included in that link. The PCH is one of the eight 20MHz bandwidth channels that make up the 160MHz bandwidth link. AP101 can notify STA110 of the PCH using a periodically broadcast Beacon frame. For example, the IEEE802.11 standard series states that the communication device 100 can start transmitting if it determines that transmission is possible as a result of performing carrier sensing on the PCH over a predetermined period. The predetermined period is determined by the Interframe Space (IFS) defined for each access category that classifies the type of communication traffic, and a random number (backoff counter) randomly determined from a predetermined range. In other words, if the communication device 100 determines that the PCH is idle over this predetermined period, it acquires the right to transmit using that link. In this case, if channels other than the PCH were idle during the PIFS period immediately preceding the start of transmission, the communication device 100 may perform transmission by channel bonding using the idle channel and the PCH. PIFS is an abbreviation for Priority Interframe Space. Furthermore, if the communication device 100 determines that transmission is not possible as a result of carrier sensing on the PCH, it may postpone transmission even if other channels included in the same link are idle. Note that each channel other than the PCH that constitutes a single link may be called a secondary channel (SCH). A secondary channel may also be called a non-primary channel (NPCH).

[0015] In communication device 100, when a signal is being received on a certain channel, if a signal is transmitted on another channel (e.g., an adjacent channel etc.) arranged at a frequency close to that channel, the received signal may not be properly received. For example, assume that communication device 100 can simultaneously perform transmission processing and reception processing using different channels. When communication device 100 is receiving on a certain channel and transmitting on an adjacent channel, the power of the transmission signal leaks into the channel of the reception signal, causing interference to the reception signal. Generally, the power due to such leakage of the transmission signal is much larger than the reception power of the reception signal, so the reception signal is not properly received. To avoid such a situation, in the IEEE802.11 standard series, a mechanism is provided to prevent another communication device from transmitting a signal using a channel adjacent to the PCH to the communication device while the communication device is transmitting a signal. For example, a PCH is provided as a channel commonly used among communication devices for determining whether transmission is possible or not. While one communication device is transmitting using the PCH, it is stipulated that the other communication device does not perform transmission even if other channels are in an idle state. Thereby, while the communication device is transmitting a signal and the PCH is being used, since other communication devices do not transmit a signal using a channel adjacent to the PCH, a situation where the communication device receives a signal on the adjacent channel does not occur. With such a configuration, the problem of interference due to power leakage occurring between the above-mentioned channels can be solved.

[0016] However, as the IEEE 802.11 standard series has expanded, the bandwidth used in a single link has increased, and as described above, communication methods that always use a PCH may not be able to efficiently utilize frequency resources. For example, if other idle channels (NPCHs) are not used based on the PCH being busy, it can hinder the efficient use of frequency resources across the entire link. Figure 2(A) shows an example of a time chart when STA111 transmits data to AP101. In Figure 2(A), STA111 performs carrier sensing on the PCH, confirms that it is idle, and then transmits data using the 20MHz bandwidth PCH. In this case, for example, even if the seven NPCHs other than the PCH are idle, other communication devices are not allowed to communicate using the NPCHs. Figure 2(B) shows another example of a time chart when STA111 transmits data to AP101. In Figure 2(B), while STA111 is performing carrier sensing on the PCH, another network geographically close to STA111 (for example, network 122 in Figure 1) is using the PCH. In this case, STA111 determines that the PCH is busy during carrier sensing, so even if the other seven NPCHs are idle, for example, STA111 is not allowed to communicate with AP101 using the NPCHs. However, since AP101 is not transmitting at this time, even if STA111 were to transmit to AP101 using the NPCHs, AP101 could properly receive the signal transmitted by STA111. Thus, if, for example, a 20MHz bandwidth PCH is being used by another network, the remaining 140MHz of idle NPCHs cannot be utilized, resulting in inefficient use of frequency resources.

[0017] In contrast, if the PCH is being used by another communication device, the communication device 100 may, based on certain conditions, choose not to use the PCH and instead use an NPCH included in the same link as the PCH to communicate between communication devices. As an example, the communication device 100 sets up a Secondary Primary Channel (SPCH) to acquire the right to transmit using an NPCH when the PCH is busy. The SPCH is one or more channels among the NPCHs included in the same link as the PCH. Note that the SPCH may be called by other names, for example, a Primary Secondary Channel (PSCH). If the communication device 100 determines that the PCH is being used by a communication device in another network (OBSS), it then determines whether transmission is possible on the SPCH. If the communication device 100 determines that transmission is possible on the SPCH, it transmits using one or more NPCHs including the SPCH. In this embodiment, the communication method of transmitting using one or more channels including the SPCH without using the PCH is called NPCH access (Non-Primary Channel Access). NPCH access may be called NPCA. This communication method may also be called by other names. For example, this communication method may be called SCA (Secondary Channel Access). In this way, when the communication device 100 acquires the right to transmit using the first channel (PCH), it communicates using a first communication method configured to enable communication by bonding the first channel with a second channel (NPCH) that is different from the first channel. On the other hand, if the communication device cannot use the first channel, when predetermined conditions are met, it acquires the right to transmit using the SPCH included in the second channel and communicates using a second communication method that uses the second channel. Predetermined conditions may be, for example, that the PCH is being used by OBSS and the SPCH is not being used. By configuring communication to use multiple communication methods including these, the communication device 100 can communicate efficiently by using the NPCH, which has less impact on the PCH, even when the PCH is being used.Note that in the first communication method, the communication device 100 may use only the PCH without using the NPCH.

[0018] Here, in communication using NPCA, not only does the transmitting communication device switch the channel for performing the carrier sense operation from the PCH to the SPCH, but the receiving communication device also needs to switch the channel for performing the monitoring operation from the PCH to the SPCH. The monitoring operation in the receiving communication device is, for example, an operation of waiting for a signal transmitted on a predetermined channel for reception when the communication device does not have data to transmit. However, due to the geographical relationship between each communication device 100 and the communication device constituting the OBSS, the channels on which the transmitting communication device and the receiving communication device each perform operations may not match. For example, as shown in Fig. 2(B), assume that STA111 is trying to transmit data to AP101 when the PCH is being used in network 122. At this time, if AP102 of network 122 is transmitting a signal on the PCH, as shown in Fig. 1, that signal is received by both AP101 and STA111. Therefore, in this case, each of AP101 and STA111 can perform NPCA by switching the channel for performing the operation to the SPCH. In this case, communication using NPCA can succeed. However, when STA113 of network 122 is transmitting a signal on the PCH, that signal is received by STA111 but not by AP101. For this reason, STA111 switches the channel for performing the carrier sense operation to the SPCH, but AP101 does not switch the channel for performing the monitoring operation to the SPCH. As a result, the signal transmitted by STA111 in the NPCH including the SPCH is not received by AP101, and the communication may fail. Thus, even for signals communicated in the same OBSS, the communication devices that receive the signal may be different depending on the communication device that transmitted the signal. This can result in a situation where one communication device switches the channel for operating for communication using NPCA while the other communication device does not switch the channel for operating.

[0019] Furthermore, suppose AP102 on network 122 is transmitting a signal on the PCH, and AP101 is attempting to transmit data to STA111 or STA112. In this case, as above, AP101 and STA111 could each switch the channel on which they operate to the SPCH and perform NPCA. However, the signal transmitted by AP102 is not received by STA112. Therefore, STA112 does not switch the channel on which it performs monitoring operations to the SPCH. As a result, the signal transmitted by AP101 on the NPCH, including the SPCH, may not be received by STA112, and communication may fail. Thus, even if STA110 is participating in the same network 121, it may not receive the OBSS signal due to its different geographical location. Therefore, if communication using NPCA is performed simply based on the reception of signals communicated on OBSS, a situation may arise where one communication device switches the channel on which it operates for communication using NPCA, while the other communication device does not switch the channel on which it operates.

[0020] In light of these circumstances, the communication device 100 in this embodiment performs communication using NPCA based on the fact that the received frame was transmitted from an AP when the received frame received in the PCH is a wireless frame communicated in a specific OBSS. Furthermore, the communication device 100 performs communication using the first communication method without using NPCA based on the fact that the received frame was transmitted from a non-access point station (non-AP STA) other than an access point. A non-AP STA is an STA that does not perform AP operations. A non-AP STA can be an STA that is not included in an AP. A specific OBSS can be an OBSS in which wireless frames transmitted by APs constituting this specific OBSS are received by both the device itself (e.g., AP101) and the other party's communication device (e.g., STA111). By performing communication using NPCA based on the reception of a wireless frame communicated in an OBSS that is also detected by the other party's communication device, the possibility of the other party's communication device not performing NPCA at that time can be reduced. Furthermore, by not using NPCA communication when receiving a wireless frame transmitted by a non-AP STA, the possibility of attempting to use NPCA communication when the other party's communication device is not using NPCA can be further reduced. For example, a non-AP STA may move geographically over time. Due to the movement of an OBSS non-AP STA, wireless frames transmitted by that non-AP STA may no longer be received by the other party's communication device. In this case, if an attempt is made to use NPCA communication based on the reception of the wireless frame transmitted by that non-AP STA, the other party's communication device may be in a situation where it is not using NPCA. By not using NPCA communication when receiving a wireless frame transmitted by a non-AP STA, this situation can be avoided. An example configuration and processing example of a communication device 100 that operates in this manner is described below.

[0021] (Device configuration) Figure 3 shows an example of the hardware configuration of the communication device 100 in this embodiment. As an example of its hardware configuration, the communication device 100 includes, for example, a storage unit 301, a control unit 302, a function unit 303, an input unit 304, an output unit 305, a communication unit 306, and an antenna 307. The communication device 100 may have multiple antennas.

[0022] The storage unit 301 is composed of one or more memories, including ROM and RAM, and may store control programs for various operations of each functional unit constituting the communication device 100, as well as various information such as parameters for communication. ROM and RAM are abbreviations for Read Only Memory and Random Access Memory, respectively. In addition to memories such as ROM and RAM, the storage unit 601 may also be composed of storage media such as flexible disks, hard disks, optical disks, magneto-optical disks, CD-ROMs, CD-Rs, magnetic tapes, non-volatile memory cards, and DVDs.

[0023] The control unit 302 is composed of one or more processors, such as a CPU and an MPU, and controls the entire communication device 100 by executing a control program stored in the memory unit 301. Alternatively, the control unit 302 may control the entire communication device 100 through cooperation between the control program stored in the memory unit 301 and the OS (Operating System). CPU and MPU are abbreviations for Central Processing Unit and Micro Processing Unit, respectively. If the control unit 302 has multiple processors, such as a multi-core processor, it may be configured so that the entire communication device 100 is controlled by multiple processors.

[0024] Furthermore, the control unit 302 controls the functional unit 303 to perform predetermined processes such as communication, imaging, printing, and projection. The functional unit 303 is hardware that enables the communication device 100 to perform the predetermined processes described above. For example, if the device is a camera, the functional unit 303 is the imaging unit and performs imaging processing. Also, for example, if the device is a printer, the functional unit 303 is the printing unit and performs printing processing. Also, for example, if the device is a projector, the functional unit 303 is the projection unit and performs projection processing.

[0025] The input unit 304 receives various operations from the user. The output unit 305 outputs various information to the user via a monitor screen or speaker. The output from the output unit 305 may be a display on the monitor screen, audio output via a speaker, vibration output, etc. The input unit 304 and the output unit 305 may both be implemented in a single module, such as a touch panel. The input unit 304 and the output unit 305 may each be an integrated device with the communication device 100, or they may be separate devices.

[0026] The communication unit 306 controls wireless communication compliant with the IEEE 802.11bn standard. In addition to the IEEE 802.11bn standard, the communication unit 306 may also control wireless communication compliant with other IEEE 802.11 standard series, such as legacy standards. The communication unit 306 controls the antenna 307 to transmit and receive signals for wireless communication generated by the control unit 302. The communication unit 306 is a so-called wireless chip and may itself include one or more processors and memory. If the communication device 100 supports other wireless communication standards such as NFC and Bluetooth, or wired communication such as wired LAN, in addition to the IEEE 802.11bn standard, the communication unit 306 may control communication compliant with these communication standards. Furthermore, if the communication device 100 can perform wireless communication compliant with multiple communication standards, the communication device 100 may have separate communication units and antennas corresponding to each communication standard. The communication device 100 communicates data with the other communication device via the communication unit 306. The antenna 307 may be configured separately from the communication unit 306, or it may be configured as a single module together with the communication unit 306. If the communication device 100 is configured to perform carrier sensing of multiple SPCHs simultaneously, the communication device 100 may be provided with the necessary number of communication units 306 for that purpose.

[0027] Antenna 307 is an antenna capable of communication in the 2.4GHz band, 5GHz band, 6GHz band, and millimeter wave bands such as 45GHz and 60GHz. Figure 3 shows a configuration in which the communication device 100 has two antennas 307, but the communication device 100 may have one or more antennas, and may have one or more antennas for each frequency band that the device can use. Also, if the communication device 100 has multiple antennas, the communication device 100 may have a communication unit 306 for each antenna. Antenna 307 may be physically composed of two or more antennas in order to realize (Multi-Input and Multi-Output) transmission and reception.

[0028] (Functional Configuration) Figure 4 shows an example of the functional configuration of the communication device 100. The functional configuration in this embodiment is an example of a functional configuration realized by, for example, one or more processors executing programs stored in one or more memories. The communication device 100 may include a wireless communication control unit 401, an OBSS detection unit 402, an information acquisition unit 403, an information notification unit 404, an OBSS identification unit 405, a frame identification unit 406, and a source determination unit 407.

[0029] The wireless communication control unit 401 communicates with other communication devices using the communication unit 306. For example, the wireless communication control unit 401 performs carrier sensing of the PCH, SPCH, and NPCH, and communicates using either a first or second communication method based on the status of each channel (idle state, busy state). For example, if the PCH is in an idle state, the wireless communication control unit 401 communicates using the first communication method. On the other hand, if the PCH is in a busy state, the wireless communication control unit 401 determines whether a predetermined condition is met, and if the predetermined condition is met, communicates using the second communication method.

[0030] The OBSS detection unit 402 detects OBSS present around the communication device 100. For example, the OBSS detection unit 402 detects an OBSS based on the fact that the BSS identification information contained in the Beacon frame received in the PCH by the communication unit 306 differs from the identification information of its own BSS. The BSS identification information may include the BSSID and BSS Color. BSSID is an abbreviation for BSS Identifier. For example, by including information indicating the BSSID and BSS Color in the Beacon frame, the BSS from which this Beacon frame was communicated can be identified. The information acquisition unit 403 acquires information from the other party's communication device. For example, the information acquisition unit 403 may acquire specific information from the other party's communication device that identifies the OBSS detected in the other party's communication device. The information notification unit 404 notifies the other party's communication device of the information. For example, the information notification unit 404 notifies the other party's communication device of specific information that identifies the OBSS detected by the OBSS detection unit 402. The OBSS Identification Unit 405 identifies OBSS detected in both its own device and the other party's communication device. For example, the OBSS Identification Unit 405 can identify OBSS detected in both communication devices as those that match the OBSS indicated by the identification information acquired by the Information Acquisition Unit 403, among the OBSS detected in the OBSS Detection Unit 402. Note that one or more of the OBSS Detection Units 402 to Information Notification Units 404 may be included in the OBSS Identification Unit 405.

[0031] The frame identification unit 406 identifies whether the received wireless frame is a wireless frame communicated in OBSS. For example, the frame identification unit 406 can identify that the received wireless frame is a wireless frame communicated in OBSS based on the fact that the received wireless frame does not contain information indicating the BSSID of its own BSS. The frame identification unit 406 can also identify whether the OBSS identified by the information contained in the wireless frame received in the PCH matches the OBSS identified in the OBSS identification unit 405. If they match, the frame identification unit 406 can identify that the received wireless frame is a wireless frame communicated in OBSS.

[0032] The source determination unit 407 determines whether the received wireless frame was transmitted by an AP or by a non-AP STA. For example, the source determination unit 407 may determine that the received wireless frame was transmitted by an AP based on the information contained in the received wireless frame. Alternatively, the source determination unit 407 may determine that the received wireless frame was transmitted by a non-AP STA based on the information contained in the received wireless frame.

[0033] (Process flow) The following describes some examples of the processing flow performed by AP101 and STA110 in this embodiment. First, Figure 5 will be used to describe an overview of the communication performed between AP101 and STA110. Figure 5 shows an example of the communication sequence performed between AP101 and STA111 in Figure 1. In addition to the wireless frames communicated between AP101 and STA111, Figure 5 also shows wireless frames transmitted by AP102, AP103, and STA113 as wireless frames communicated in OBSS. This sequence may start, for example, when the power to STA111 is turned on and STA111 starts up. When STA111 starts up, it starts connecting to AP101. For example, AP101 may periodically transmit Beacon frames (F501). The Beacon frame may include the identifier of the BSS (self-BSS) provided by AP101 (e.g., BSSID), AP101 capability information, communication parameters that can be used for communication with AP101, etc. When STA111 detects the presence of AP101 by receiving a Beacon frame transmitted by AP101, it may initiate a connection procedure to AP101. For example, as part of the connection procedure to AP101, STA111 first sends a Probe Request frame (F502). AP101 responds to the Probe Request frame by sending a Probe Response frame (F503). Subsequently, AP101 and STA111 perform authentication of each other's communication devices by exchanging Authentication frames (F504). Once authentication is complete, STA111 sends an Association Request frame to AP101 (F505). AP101 responds to the Association Request frame by sending an Association Response frame (F506). Through this connection procedure, a connection is established between AP101 and STA111. Note that the connection procedure between AP101 and STA111 is not limited to the above, and may include other steps, or some steps may be omitted.For example, after AP101 sends an Association Response frame, a 4-Way handshake may be performed to exchange security information.

[0034] In this connection procedure, STA111 may notify AP101 of its capabilities. For example, STA111 may notify AP101 of information indicating that it has the capability to perform communication using NPCA. STA111's capabilities may be notified using, for example, a Probe Request frame or an Association Request frame. Similarly, AP101 may notify STA111 of its capabilities in this connection procedure. For example, AP101 may notify STA111 of information indicating that it has the capability to perform communication using NPCA. AP101's capabilities may be notified using, for example, a Beacon frame, a Probe Response frame, or an Association Response frame. By sharing their respective capabilities with the other communication device, AP101 and STA111 can mutually recognize that they each have the capability to perform communication using NPCA.

[0035] AP101 and STA111 may perform negotiation to perform communication using NPCA (F509). Negotiation for communication using NPCA may be called NPCA negotiation. For example, AP101 and STA111 may initiate NPCA negotiation based on information indicating that the other device has the capability to perform communication using NPCA. NPCA negotiation may be initiated by AP101 or by STA111. In NPCA negotiation, STA111 may notify AP101 of information identifying the OBSS detected by its own device on the PCH. For example, STA111 may receive a Beacon frame transmitted by AP102 in F507. In this case, STA111 may retain information indicating the BSSID contained in the received Beacon frame. The BSSID is identification information for identifying the BSS to which the communication device that transmitted the wireless frame participates. The MAC address of the AP providing the BSS may be used as the BSSID. Furthermore, if STA111 receives multiple Beacon frames transmitted from multiple different APs on the PCH, it can retain the BSSID contained in each Beacon frame. Then, during NPCA negotiation, STA111 notifies AP101 of information that identifies the OBSS it holds. For example, STA111 may notify AP101 of the BSSID of network 122, which is configured by AP102. Similarly, AP101 may notify STA111 of information that identifies the OBSS it has detected on the PCH. For example, AP101 may receive a Beacon frame transmitted by AP102 at F507. Also, AP101 may receive a Beacon frame transmitted by AP103 at F508. In this case, AP101 can retain information indicating the BSSID contained in each of the received Beacon frames. For example, AP101 may retain the BSSID of network 122 and the BSSID of network 123. Note that the BSSID of network 122 could be the MAC address of AP102. Also, the BSSID of network 123 could be the MAC address of AP103.Furthermore, during NPCA negotiation, AP101 can notify STA111 of the BSSIDs of network 122 and network 123 that it holds. This allows each communication device to share information that identifies the OBSS detected on the PCH. AP101 and STA111 identify the OBSS detected in both communication devices. For example, network 122 is identified as the OBSS detected in both communication devices. The OBSS identified in this way is used in the conditions for executing communication using NPCA, which will be described later.

[0036] Alternatively, STA111 may identify the OBSS detected on the PCH in both its own device and AP101, and notify AP101 of the information indicating the identified OBSS, without notifying AP101 of the information identifying the OBSS detected by its own device on the PCH. For example, AP101 may periodically transmit a Beacon frame containing a list of information identifying the OBSS detected by its own device on the PCH. In this case, STA111 can identify the OBSS detected in both its own device and AP101 by using the information identifying the OBSS obtained from the list contained in the received Beacon frame and the information identifying the OBSS held in its own device. AP101 can identify the OBSS detected in both its own device and STA111 by being notified by STA111 of the information indicating the identified OBSS. Similarly, AP101 may identify the OBSS detected in the PCH in both its own device and STA111 without notifying STA111 of the information that identifies the OBSS detected in the PCH by its own device, and then notify STA111 of the information indicating the identified OBSS. For example, AP101 may obtain from STA111 the information that identifies the OBSS detected in the PCH by STA111. STA111 may, as described above, provide AP101 with a list of information that identifies the detected OBSS. In this case, AP101 can identify the OBSS detected in both its own device and STA111 using the information indicating the OBSS obtained from STA111 and the information that identifies the OBSS held in its own device. STA111 can identify the OBSS detected in both its own device and AP101 by being notified from AP101 of the information indicating the OBSS identified by AP101. Thus, the procedure by which one communication device 100 identifies the OBSS detected by both communication devices and notifies the other communication device of information indicating the identified OBSS can be performed as a unilateral notification rather than as a negotiation between communication devices. Note that the information used to identify the OBSS is not limited to the BSSID of that OBSS. For example, information indicating the BSS Color included in the physical layer preamble of the PPDU may be used as the information used to identify the OBSS.The BSS Color is identification information that indicates the BSS to which the communication device that transmitted the PPDU is participating. The physical layer preamble can also be called the PHY preamble.

[0037] Once NPCA negotiation is complete, AP101 and STA111 can communicate by switching between a first communication method, which uses the PCH to acquire transmission rights, and a second communication method, which uses NPCA. For example, AP101 and STA111 normally communicate using the first communication method, and switch to the second communication method when certain conditions are met. The predetermined conditions are, for example, that both AP101 and STA111 have received a radio frame from an OBSS communication detected on the PCH (first condition). Another predetermined condition may be that the radio frame received on the PCH has been transmitted by the AP (second condition). AP101 and STA111 switch from the first communication method to the second communication method when both the first and second conditions are met. This prevents a situation where one communication device switches the channel on which it operates to the SPCH in order to perform NPCA, but the other communication device does not make that switch. When the first condition is met, channel switching, in which only one communication device operates, is avoided based on the reception of radio frames from an OBSS that is received by one communication device but not by the other. Here, among the OBSSs detected by both communication devices, there may be OBSSs in which radio frames transmitted by an STA participating in that OBSS are received by one communication device but not by the other due to the movement of that STA. In contrast, APs are likely to be fixed in place. In contrast, when the second condition is met, channel switching, in which only one communication device operates, is avoided based on the reception of radio frames transmitted by an STA that is likely to move.

[0038] In Figure 5, STA111 can receive a data frame transmitted from STA113 on network 122 to AP102 (F510). In F510, the arrows from STA113 to AP102 and STA111 indicate that the data frame transmitted by STA113 is received by AP102 and STA111, respectively. STA111 determines that the first condition is met based on the fact that the received data frame is a wireless frame communicated on network 122. On the other hand, STA111 determines that the second condition is not met because the received data frame was transmitted by STA113, which is a non-AP STA. As a result, STA111 communicates using the first communication method without switching the channel on which it operates to SPCH. In this case, STA111 can set the period corresponding to TXOP F511, in which PCH is used, as NAV for its own device. Note that the data frame transmitted by STA113 does not reach AP101. In this case, AP101 communicates using the first communication method. At this time, AP101 does not have NAV set for the period corresponding to TXOP F511, so if there is data destined for STA111 in AP101, AP101 may attempt to transmit using PCH. However, during the period when NAV is set on the PCH in STA111, even if STA111 receives a radio frame from AP101, it will not respond to that radio frame.

[0039] On the other hand, AP101 and STA111 can receive data frames transmitted from AP102 to STA113 on network 122 (F512). In F512, the arrows pointing from AP102 to STA113, STA111, and AP101 indicate that the data frame transmitted by AP102 is received by STA113, STA111, and AP101, respectively. AP101 and STA111 determine that the first condition is met based on the fact that the received data frame is a wireless frame communicated on network 122. AP101 and STA111 also determine that the second condition is met because the received data frame was transmitted by AP102. As a result, AP101 and STA111 switch the channel on which they will perform their operation to SPCH and communicate using NPCA. For example, if AP101 determines that it is possible to transmit on SPCH, it may transmit a data frame to STA111 using NPCH including SPCH (F514). Furthermore, AP101 and STA111 can set the period corresponding to TXOP F513 in which PCH is used on network 122 as NAV for their own devices. For example, when the NAV expires, AP101 and STA111 can switch from the communication method using NPCA to the first communication method and continue communication.

[0040] Furthermore, AP101 may receive a data frame transmitted by AP103 on network 123 (F515). AP101 determines that the first condition is not met based on the fact that the received data frame is a wireless frame communicated on network 123. As a result, AP101 communicates using the first communication method without switching the channel on which it operates to SPCH. In this case, AP101 may set the period corresponding to TXOP F516, during which PCH is used, as NAV for its own device. Note that STA111 does not receive the data frame transmitted by AP103. In this case, STA111 communicates using the first communication method. When TXOP F516 expires, AP101 transmits data to STA111 using the first communication method (F517).

[0041] In this way, AP101 and STA111 identify the OBSS detected in both communication devices during NPCA negotiation, and determine whether the received frame received on the PCH satisfies the first and second conditions based on the identified OBSS. Then, based on the fact that the first and second conditions are met, AP101 and STA111 switch the channel on which they perform their operation to the SPCH and communicate using NPCA. This prevents a situation where only one communication device switches the channel on which it performs its operation, while the other communication device does not.

[0042] (Wireless frame configuration) This section describes an example of the configuration of a wireless frame used for communication between communication devices. AP101 and STA111 can determine the first and second conditions based on the information contained in the received wireless frame. Figures 6(A) and 6(B) show an example of the PPDU frame format used when AP101 or STA111 transmits data. The PPDU shown in Figures 6(A) and 6(B) is an example of an HE PPDU as defined in the IEEE 802.11ax standard. HE is an abbreviation for High Efficiency. HE PPDU includes L-STF601, L-LTF602, L-SIG603, RL-SIG604, HE-SIG-A605, HE-STF606, HE-LTF607, Data608, and PE609. L-STF601 to HE-LTF607 may be called the physical (PHY) preamble. L-STF and L-LTF are abbreviations for Legacy-Short Training Field and Legacy-Long Training Field, respectively. L-SIG is an abbreviation for Legacy-Signal Field. RL-SIG is an abbreviation for Repeated L-SIG. HE-SIG is an abbreviation for HE-Signal. HE-STF is an abbreviation for HE-Short Training Field. HE-LTF is an abbreviation for HE-Long Training Field. PE is an abbreviation for Packet Extension.

[0043] L-STF601, L-LTF602, and L-SIG603 are placed at the beginning of the PHY preamble and provide backward compatibility to the legacy standard-compliant communication device 100. These fields are sometimes collectively referred to as the legacy preamble. For example, L-STF601 is used in the receiving communication device 100 for processing such as PPDU detection, automatic gain control (AGC), and timing detection. L-LTF602 is used in the receiving communication device 100 for processing such as high-precision synchronization of frequency and time, and acquisition of propagation channel information (also called Channel State Information, CSI). L-SIG603 is used to notify the receiving communication device 100 of control information such as data rate and PPDU frame length. The receiving communication device 100 can use the data rate and PPDU frame length information notified by L-SIG603 to determine the timing when PPDU transmission or reception is completed. RL-SIG604 can be a repetition of L-SIG603. Placing RL-SIG604 after L-SIG603 may indicate that the PPDU conforms to the frame format used in standards from IEEE 802.11ax onwards.

[0044] HE-SIG-A605 is used to notify control information for performing communication compliant with the IEEE 802.11ax standard. HE-STF606 and HE-LTF607 are training fields used for estimating channel information when using MIMO or beamforming. MIMO is an abbreviation for Multiple Input Multiple Output. Multiple HE-LTF607s may be placed in a single PHY preamble. The number of HE-LTF607s to be placed may be determined based on, for example, the number of antennas used for MIMO or whether beamforming is performed. An HE-SIG-B field may be placed between HE-SIG-A605 and HE-STF606. Data608 contains data input from a higher layer. For example, the data may be an MPDU (MAC Protocol Data Unit). MAC is an abbreviation for Medium Access Control. PE609 is used to provide additional reception processing time to the receiving communication device 100.

[0045] Figure 6(B) shows an example configuration of HE-SIG-A605. For example, HE-SIG-A605 includes a UL / DL field that indicates whether the PPDU is an uplink PPDU transmitted from an AP to a non-AP STA, or a downlink PPDU transmitted from a non-AP STA to an AP. For example, a value of 1 in the UL / DL field indicates that it is an uplink PPDU transmitted by a non-AP STA. A value of 0 in the UL / DL field indicates that it is a downlink PPDU transmitted by an AP. Therefore, AP101 and STA111 can determine whether a received radio frame was transmitted by an AP or a non-AP STA based on the information set in the UL / DL field of the PHY preamble, if the radio frame is an HE PPDU.

[0046] Furthermore, HE-SIG-A605 includes a BSS Color field used for BSS identification. BSS Colors can be configured to use different values ​​for neighboring BSSs. Therefore, when the received radio frame is an HE PPDU, AP101 and STA111 can identify the BSS from which the received radio frame was transmitted based on the information set in the BSS Color field included in the PHY preamble. Since the PHY preamble is located at the beginning of the PPDU, the communication device that receives the PPDU can quickly determine the action it should take by using the information contained in the PHY preamble. For example, AP101 and STA111 can determine whether the first and second conditions are met based on the information in the PHY preamble and decide whether or not to switch the operating channel to SPCH. This allows AP101 and STA111 to quickly start communication when using NPCA.

[0047] Figures 7(A) and 7(B) show another example of a PPDU frame format used when a communication device transmits data. The PPDUs shown in Figures 7(A) and 7(B) are examples of UHR PPDUs as defined in the IEEE 802.11bn standard. UHR is an abbreviation for Ultra High Reliability. In Figure 7(A), the same components as in Figure 6(A) are given the same reference numbers and their descriptions are omitted. HE PPDUs include L-STF601, L-LTF602, L-SIG603, RL-SIG604, U-SIG701, UHR-SIG702, UHR-STF703, UHR-LTF704, Data608, and PE609. U-SIG is an abbreviation for Universal Signal Field. UHR-SIG is an abbreviation for UHR-Signal. UHR-STF is an abbreviation for UHR-Short Training Field. UHR-LTF is an abbreviation for UHR-Long Training Field.

[0048] U-SIG701 is a field commonly used in standards from IEEE 802.11be onwards, and is used to notify control information for performing communication compliant with the standard. U-SIG701 can consist of two fields: U-SIG-1 707 and U-SIG-2 708. Figure 7(B) shows an example configuration of U-SIG-1 707. As shown in Figure 7(B), U-SIG-1 707, like HE-SIG-A605, includes the UL / DL field and the BSS Color field. Therefore, AP101 and STA111 can identify the BSS from which the received radio frame was communicated based on the information set in the BSS Color field of the PHY preamble, if the received radio frame is a UHR PPDU. Furthermore, if the received wireless frame is a UHR PPDU, AP101 and STA111 can determine whether the wireless frame was transmitted by an AP or a non-AP STA based on the information set in the UL / DL field included in the PHY preamble. In this way, even if the received wireless frame is a UHR PPDU, AP101 and STA111 can determine whether the first and second conditions are met based on the information in the PHY preamble. Note that the control information included in U-SIG701 and the arrangement of control information within U-SIG701 may differ depending on the standard. In this case, communication device 100 can identify the PHY version of the received PPDU based on the value of the PHY Version Identifier field included at the beginning of U-SIG-1 707. For example, communication device 100 can identify the presence or absence of the UL / DL field and BSS Color field and their location within the PHY preamble based on the value of the PHY Version Identifier field.

[0049] U-SIG-2 708 includes the PPDU type, the MCS used to generate UHR-SIG702, the number of symbols constituting UHR-SIG702, and the CRC. MCS stands for Modulation and Coding Scheme. CRC stands for Cyclic Redundancy Check. For example, the PPDU type indicates whether the PPDU is an OFDMA transmission, single-user transmission, non-OFDMA MU-MIMO transmission, trigger-based PPDU, etc. OFDMA stands for Orthogonal frequency-division multiple access. MU-MIMO stands for Multi-user-MIMO. Thus, this example can be applied to various types of PPDUs used in the IEEE 802.11bn standard. UHR-SIG702 may include control information not placed in U-SIG701, or control information that the AP should individually notify each non-AP STA when performing multi-user transmission. Multi-user transmission is a communication method in which, for example, AP101 communicates in parallel with multiple non-AP STAs using MU-MIMO or OFDMA. The name UHR-SIG is a convenient designation to identify it as a SIG field compliant with the IEEE 802.11bn standard. Therefore, the UHR-SIG field may also be called, for example, UHR-SIG-A field, UHR-SIG-B field, or another name. UHR-STF703 and UHR-LTF704 are training fields used in the same way as HE-STF606 and HE-LTF607.

[0050] The above describes configuration examples for HE PPDU as defined in the IEEE 802.11ax standard and UHR PPDU as defined in the IEEE 802.11bn standard in data communication between AP101 and STA111. As described above, AP101 and STA111 can obtain information to determine whether the first and second conditions included in the received PPDU are met, according to the frame format of HE PPDU and UHR PPDU. The frame format of the PPDU to which this example applies is not limited to HE PPDU and UHR PPDU. For example, this example can also be applied to EHT PPDU as defined in the IEEE 802.11be standard. EHT is an abbreviation for Extremely High Throughput. Like UHR PPDU, EHT PPDU has a U-SIG field in the PHY preamble. Therefore, AP101 and STA111 can determine whether the first and second conditions are met based on the information in the PHY preamble, even when the received wireless frame is an EHT PPDU. Furthermore, in PPDUs defined in standards from IEEE 802.11bn onward, the PHY preamble may include information identifying the BSS and information indicating whether the PPDU was transmitted by an AP or a non-AP STA. This information can be used to determine whether the first and second conditions are met.

[0051] The wireless frame information that AP101 and STA111 use to determine the first and second conditions is not limited to the information contained in the PHY preamble. For example, AP101 and STA111 may use the information contained in the MPDU to determine the first and second conditions. The MPDU may be called a MAC frame. Figure 8 shows an example of the structure of a MAC frame contained in a PPDU. The MAC frame includes the fields Frame Control 801, Duration / ID 802, Address1 803, Address2 804, and Address3 805. The MAC frame also includes the fields Sequence Control 806, Address4 807, QoS Control 808, and HT Control 809. Frame Control 801 to HT Control 809 may be called the MAC header. The MAC frame also includes the fields Frame Body 810 and FCS 811. Frame Control 801 includes the subfields Protocol Version 812, Type 813, Subtype 814, ToDS 815, FromDS 816, More Fragments 817, and Retry 818. Frame Control 801 also includes the subfields Power Management 819, More Data 820, Protected Frame 821, and +HTC 822. Since each field and subfield indicates information similar to that specified in the IEEE 802.11 standard series, the following description will focus on the fields and subfields that are most relevant to the processing performed in this embodiment. Note that fields and subfields other than those described below may also be used to determine the first and second conditions.

[0052] The Type subfield 813 and Subtype subfield 814 indicate the type of MAC frame. For example, if the value of the Type subfield 813 is "01", it indicates that the MAC frame is a Control frame. When the Type subfield 813 indicates a Control frame, the Subtype subfield 814 indicates that the MAC frame is an RTS frame, CTS frame, ACK frame, Block ACK frame, Trigger frame, etc. RTS is an abbreviation for Request to Send. CTS is an abbreviation for Clear to Send. ACK is an abbreviation for Acknowledgement. If the value of the Type subfield 813 is "10", it indicates that the MAC frame is a Data frame.

[0053] If the MAC frame is a data frame, the ToDS subfield 815 and FromDS subfield 816 can be used to indicate the communication direction of the MAC frame. DS is an abbreviation for Distribution System. For example, setting the ToDS subfield 815 to a value of 1 and the FromDS subfield 816 to a value of 0 indicates that it is an uplink MAC frame. Also, setting the ToDS subfield 815 to a value of 0 and the FromDS subfield 816 to a value of 1 indicates that it is a downlink MAC frame. Therefore, AP101 and STA111 can determine whether the wireless frame was transmitted by the AP or a non-AP STA based on the ToDS subfield 815 and FromDS subfield 816 of the MAC header of the received wireless frame. Note that setting both the ToDS subfield 815 and FromDS subfield 816 to a value of 0 indicates that it is a MAC frame for communication between non-AP STAs. Furthermore, setting both the ToDS subfield 815 and the FromDS subfield 816 to a value of 1 indicates that it is a MAC frame for communication such as mesh BSS.

[0054] The Address1 field 803 and Address2 field 804 display different information based on the values ​​set in the ToDS subfield 815 and FromDS subfield 816. Basically, the Address1 field 803 indicates the MAC address of the communication device 100 that should receive (send) the MAC frame. For example, in the case of an uplink MAC frame where the value of ToDS subfield 815 is set to 1 and the value of FromDS subfield 816 is set to 0, the Address1 field 803 indicates the MAC address of the AP. Note that if the MAC address of the AP is used as the BSSID to identify the BSS, the Address1 field 803 may indicate the BSSID along with the MAC address of the communication device 100 that should receive the MAC frame. Also, in the case of a downlink MAC frame where the value of ToDS subfield 815 is set to 0 and the value of FromDS subfield 816 is set to 1, the Address1 field 803 indicates the MAC address of the non-AP STA.

[0055] Basically, the Address2 field 804 indicates the MAC address of the communication device 100 that sent the MAC frame (the source). For example, in the case of an uplink MAC frame where the ToDS subfield 815 is set to a value of 1 and the FromDS subfield 816 is set to a value of 0, the Address2 field 804 indicates the MAC address of the non-AP STA. Also, in the case of a downlink MAC frame where the ToDS subfield 815 is set to a value of 0 and the FromDS subfield 816 is set to a value of 1, the Address2 field 804 indicates the MAC address of the AP. Furthermore, if the MAC address of the AP is used as the BSSID to identify the BSS, the Address2 field 804 may indicate the BSSID along with the MAC address of the communication device 100 that sent the MAC frame.

[0056] Thus, if the received MAC frame is a data frame, the OBSS that communicated the PPDU can be identified using the Address1 field 803 and the Address2 field 804. For example, AP101 and STA111 determine whether the information indicated in either the Address1 field 803 or the Address2 field 804 of the received PPDU matches the BSSID of the OBSS detected by both communication devices. If they match, the received PPDU can be identified as the PPDU communicated under the BSSID of the OBSS detected by both communication devices. Also, if the MAC frame is a data frame, the communication device that sent the PPDU can be identified based on the value set in the Address1 field 803 or the Address2 field 804. For example, AP101 and STA111 determine whether the information indicated in the Address2 field 804 matches the BSSID of the OBSS detected by both communication devices. If they match, the received PPDU can be identified as the PPDU sent by the AP of the OBSS detected by both communication devices. Furthermore, AP101 and STA111 determine whether the information indicated in Address1 field 803 matches the BSSID of the OBSS detected in both communication devices. If they match, it can be determined that the received PPDU was transmitted by a non-AP STA of the OBSS detected in both communication devices.

[0057] On the other hand, if the received MAC frame is a control frame, the ToDS subfield 815 and FromDS subfield 816 are set to a value of 0. In this case, the OBSS from which the PPDU was communicated can be identified using the Address1 field 803 and the Address2 field 804. For example, AP101 and STA111 determine whether the information indicated by either the Address1 field 803 or the Address2 field 804 of the received PPDU matches the BSSID of the OBSS detected by both communication devices. If they match, the received PPDU can be identified as a PPDU communicated in the OBSS detected by both communication devices. Furthermore, the Address1 field 803 and the Address2 field 804 can be used to determine whether the communication device that sent the PPDU is an AP or a non-AP STA. For example, AP101 and STA111 determine whether the information indicated by Address2 804 matches the BSSID of the OBSS detected by both communication devices. If they match, the received PPDU can be identified as a PPDU sent by an AP of the OBSS detected by both communication devices. Furthermore, AP101 and STA111 determine whether the information indicated in Address1 field 803 matches the BSSID of the OBSS detected in both communication devices. If they match, it can be determined that the received PPDU was transmitted by a non-AP STA of the OBSS detected in both communication devices.

[0058] Note that the information contained in the MAC frame used by AP101 and STA111 when determining the first and second conditions is not limited to the above. Figure 9 shows an example of the configuration of a Trigger frame. In Figure 9, the same reference number is used for configurations similar to those in Figure 8, and the explanation is omitted. The Trigger frame includes the fields Frame Control801, Duration / ID802, RA901, TA902, Common Info903, User Info List904, Padding905, and FCS811. RA901 indicates the MAC address of the communication device 100 that should receive the Trigger frame. TA902 indicates the MAC address of the communication device 100 that sent the Trigger frame. Common Info903 contains control information commonly used by non-AP STAs that should receive the Trigger frame. User Info List904 contains control information used individually for each non-AP STA that should receive the Trigger frame. Padding905 is used to provide the receiving communication device with sufficient time to respond. A trigger frame is used when an AP causes an STA connected to it to send an uplink PPDU. Therefore, trigger frames are sent by the AP. For example, AP101 and STA111 can identify a MAC frame as a trigger frame by the Type subfield 813 and Subtype subfield 814 contained in the MAC header of the received PPDU. In this case, AP101 and STA111 can determine that the received trigger frame is a PPDU sent by the AP. In this case, AP101 and STA111 determine whether the information indicated by TA902 matches the BSSID of the OBSS detected in both communication devices. If they match, the received PPDU can be identified as a PPDU communicated in the OBSS detected in both communication devices.

[0059] (Processing flow for AP101 and STA111) The operation of communication device 100 when communicating with the other party's communication device will be described. Figure 10 shows an example of the processing flow when communication device 100 transmits data based on NPCA negotiation performed with the other party's communication device. This processing flow may be executed when communication device 100 receives a wireless frame on the PCH after performing NPCA negotiation with the other party's communication device. Note that if communication device 100 has data stored in its own device destined for the other party's communication device, it performs carrier sense operation on the PCH. Also, if communication device 100 does not have data to be transmitted stored in its own device, it performs monitoring operation on the PCH to receive a wireless frame. The processing flow in Figure 10 can be applied to either operation.

[0060] First, the communication device 100 receives a wireless frame on the PCH (S1001). The communication device 100 analyzes the information contained in the received wireless frame. For example, the communication device 100 may obtain information indicated in the UL / DL field, BSS Color field, etc., contained in the PHY preamble of the wireless frame. The communication device 100 may also obtain information indicated in the Type subfield 813, Subtype subfield 814, ToDS subfield 815, FromDS subfield 816, etc., contained in the MAC header of the wireless frame. The communication device 100 may also obtain information indicated in the Address1 field 803, Address2 field 804, etc., contained in the MAC header of the wireless frame. Based on the obtained information, the communication device 100 determines whether the first and second conditions described above are met.

[0061] The communication device 100 determines whether the received wireless frame is a wireless frame communicated via OBSS or a wireless frame communicated via its own BSS. For example, the communication device 100 may determine whether or not a wireless frame was communicated via OBSS based on the information shown in the BSS Color field of the PHY preamble or in the Address1 field 803 and Address2 field 804 of the MAC header. As an example, if the received wireless frame was communicated via a BSS other than its own BSS, the communication device 100 may determine that it is a frame communicated via OBSS (YES in S1002). In this case, if the received wireless frame was communicated via its own BSS, the communication device 100 may determine that it is not a frame communicated via OBSS (NO in S1002). Furthermore, the communication device 100 may determine that a frame communicated via OBSS, as identified in NPCA negotiation, is a wireless frame communicated via OBSS (YES in S1002). As mentioned above, in NPCA negotiation, the OBSS detected by the PCH can be identified in both the local device and the other party's communication device. If the communication device 100 finds that the received wireless frame is not a wireless frame communicated in the OBSS identified in NPCA negotiation, it can determine that it is not a frame communicated in the OBSS (NO in S1002). If the communication device 100 finds that the received wireless frame is not a wireless frame communicated in the OBSS (NO in S1002), it will perform communication using the first communication method without using NPCA (S1005).

[0062] If the communication device 100 determines that the received wireless frame is a wireless frame communicated via OBSS (YES in S1002), it determines whether the wireless frame was transmitted by an AP or a non-AP STA. For example, the communication device 100 may determine whether the received wireless frame was transmitted by an AP or a non-AP STA based on the information shown in the UL / DL field of the PHY preamble. The communication device 100 may also determine the source of the received wireless frame based on the information shown in the ToDS subfield 815, FromDS subfield 816, Address1 field 803, Address2 field 804, etc., of the MAC header. If the communication device 100 determines that the received wireless frame was transmitted by an AP (YES in S1003), it performs communication using NPCA (S1004). For example, if data destined for the other communication device is stored in the communication device 100, it performs carrier sense operation with SPCH. Furthermore, if the communication device 100 does not have any data to be transmitted stored on its own, it performs a monitoring operation to receive wireless frames on the SPCH. On the other hand, if the received wireless frame is a wireless frame transmitted by a non-AP STA (NO in S1003), the communication device 100 performs communication using the first communication method without using NPCA (S1005). For example, if the communication device 100 has data stored on its own that is destined for the other communication device, it waits to transmit until the PCH becomes idle without switching the operating channel, and then resumes carrier sense operation on the PCH. Also, if the communication device 100 does not have any data to be transmitted stored on its own, it performs a monitoring operation to receive wireless frames on the PCH without switching the operating channel.

[0063] Furthermore, the communication device 100 may decide whether or not to perform a determination of the first and second conditions based on the type of OBSS radio frame received on the PCH and the period for which the PCH is used as indicated in the radio frame. For example, the communication device 100 may decide to perform a determination of the first and second conditions when it receives a data frame or a predetermined control frame. When a data frame is received on the PCH, the PCH is reserved for the period indicated in the Duration field of that data frame, and data communication can take place. The period indicated in the Duration field may be the time required to exchange one data frame, or it may be a TXOP in which multiple data frames are exchanged. Thus, when a data frame is received on the PCH, there is a high probability that the PCH will be occupied for a certain length of time. Therefore, AP101 and STA111 may switch the channel on which they perform their respective operations to the SPCH and perform communication using NPCA. In addition, the Duration field included in the ACK frame and Block ACK frame may indicate the remaining time of the TXOP. Therefore, AP101 and STA111 can decide whether to switch the channel on which they are performing their respective operations to SPCH and perform communication using NPCA, depending on the remaining time (for example, if it is longer than a predetermined time). In addition, RTS frames and CTS frames can be used to reserve a channel prior to the transmission of a data frame. Trigger frames can be used by the AP to send an uplink data frame to a non-AP STA. Therefore, AP101 and STA111 can decide whether to switch the channel on which they are performing their respective operations to SPCH and perform communication using NPCA, depending on the period during which the PCH indicated in these control frames is used.

[0064] (modified version) Before executing the data communication flow shown in Figure 10, AP101 and STA111 may each decide what type of information they will use to determine the first and second conditions. Determining what type of information to use to determine the first and second conditions may involve deciding which information to use from the information contained in each field and subfield of the PHY preamble and MAC header of the received frame. For example, if AP101 and STA111 support different standards, the information they can use from the received wireless frame may differ. For example, if AP101 supports all standards released before the IEEE 802.11be standard, AP101 can use the UL / DL field and BSS Color field contained in the PHY header of the PPDU. On the other hand, if STA111 does not support standards released after the IEEE 802.11ax standard, STA111 cannot use the UL / DL field and BSS Color field contained in the PHY preamble of the PPDU. This is because the PHY preamble of the PPDU specified in the standards that STA111 can receive and process does not include the UL / DL field or the BSS Color field. Therefore, if the information available to each communication device 100 is different, there is a possibility that only one communication device 100 will switch the channel on which it operates, or that the timing of channel switching between each communication device 100 will differ significantly. To avoid such a situation, AP101 and STA111 predetermine the type of information to be used to determine the first and second conditions. This prevents situations where the switching of operating channels differs between communication devices 100 due to different types of information used by each communication device 100. For example, AP101 and STA111 may determine the type of information to be used to determine the first and second conditions during NPCA negotiation. Alternatively, communication device 100 may determine the information to be used to determine the first and second conditions based on the standard it supports and the standard supported by the other communication device.In this case, it can be determined that the types of information contained in the frame format specified in the standards of both communication devices can be used to determine the first and second conditions. By pre-determining the types of information to be used to determine the first and second conditions between AP101 and STA111 in this way, it is possible to avoid the communication devices performing operations to execute NPCA communication based on different types of information.

[0065] Communication device 100 may update the identification of OBSS detected in both its own device and the other party's communication device. For example, if STA111 is a mobile communication device, the OBSS detected in the PCH may change as the device moves. As a result, if the OBSS detected in both AP101 and STA111 changes, one communication device may switch the channel it operates on to communicate using NPCA, while the other communication device does not. To address this, communication device 100 may update the information identifying the OBSS detected in the PCH by its own device and notify the other party's communication device. For example, communication device 100 may periodically perform OBSS detection processing in the PCH even after NPCA negotiation and notify the other party's communication device of the results. Furthermore, if the OBSS detected in the PCH changes in both communication devices, communication device 100 may update the OBSS that is subject to the determination of the first and second conditions. This allows for appropriate judgment to be made in response to changes in the OBSS detected by the PCH when the communication device 100 moves. The communication device 100 also retains the detection results of the OBSS it has performed and can notify the other communication device if the detection result of a newly performed OBSS detection process differs from the retained detection result. As a result, if there is no change in the detection result, the other communication device will not be notified, thus reducing the amount of information to be communicated.

[0066] As described above, according to this embodiment, the communication device 100 performs communication using NPCA based on the reception of wireless frames communicated in OBSS detected by both its own device and the other party's communication device. This reduces the possibility that the other party's communication device may not have switched channels when the own device switches channels to operate for NPCA communication. Furthermore, the communication device 100 performs communication using NPCA based on the reception of wireless frames transmitted by AP, and does not perform communication using NPCA when it receives wireless frames transmitted by a non-AP STA. This further reduces the possibility that the other party's communication device may not have switched channels when the own device switches channels to operate for NPCA communication. Thus, according to this embodiment, the communication device 100 does not waste wireless resources by transmitting wireless frames even when the other party's communication device is not operating in SPCH, thus enabling efficient use of wireless resources. Furthermore, when the other party's communication device does not switch the operating channel, the communication device 100 will not perform the switching itself, thus eliminating the consumption of power for operation and channel switching. This allows the communication device to operate more efficiently.

[0067] In this embodiment, a communication method that does not use a PCH is exemplified as NPCH access, but it is not limited to this, and may be called, for example, Secondary Primary Channel Access. In this embodiment, a channel used to determine whether or not transmission using an NPCH is permitted is conveniently referred to as SPCH, but it is not limited to this. Among multiple NPCHs, it may be called PSCH (Primary Secondary Channel) to mean a channel with a high priority for determining whether or not transmission is permitted. Similarly, it may be called NPCA Primary Channel. In any case, it means that it is a channel that should be used to determine whether or not transmission using an NPCH is permitted.

[0068] The present invention can also be realized by supplying a program that implements one or more of the functions of the above-described embodiments to a system or device via a network or storage medium, and by having one or more processors in the computer of that system or device read and execute the program. It can also be realized by a circuit (e.g., an ASIC) that implements one or more functions.

[0069] (Summary of the embodiments) At least some of the embodiments described above can be summarized as follows: (Item 1) A communication device that communicates with other communication devices using wireless frames compliant with the IEEE 802.11 standard series, A first communication method configured to enable communication by bonding a first channel and a second channel different from the first channel, comprising: a first communication method that acquires transmission rights and performs communication using the first channel; and a second communication method that acquires transmission rights and performs communication using the second channel when the first channel cannot be used; and a communication means that performs communication using a plurality of communication methods. An Overlapping Basic Service Set (OBSS) comprising the aforementioned communication device and an access point different from the other communication devices, comprising identification means for identifying the OBSS in which the wireless frame transmitted by the access point is received by both the communication device and the other communication devices on the first channel, The communication means, when the received frame received on the first channel after the identification is the wireless frame communicated in the identified OBSS, Based on the fact that the received frame was transmitted from the access point, communication is performed using the second communication method. Based on the fact that the received frame was transmitted from a non-access point station other than the access point, communication is performed using the first communication method instead of the second communication method. A communication device characterized by the following features. (Item 2) The aforementioned specifying means is, A detection means for detecting OBSS in the first channel, The device includes an acquisition means for acquiring specific information indicating OBSS detected in the first channel by the other communication device from the other communication device, Based on the OBSS detected by the detection means and the OBSS indicated by the identification information, the identification of the OBSS is performed. A communication device as described in item 1, characterized by the features described herein. (Item 3) The identification means further includes a notification means for notifying the other communication device of the identification information indicating the OBSS detected by the detection means. A communication device as described in item 2, characterized by the features described herein. (Item 4) The notification means maintains information indicating the OBSS detected in the first channel and makes the notification based on the detection of a new OBSS not included in the information, or the fact that no more OBSS included in the information are detected. A communication device as described in item 3, characterized by the features described herein. (Item 5) The system further includes identification means for identifying that the received frame is the wireless frame communicated in the OBSS. A communication device characterized by any one of items 1 to 4. (Item 6) The identification means identifies that the received frame is the wireless frame communicated in the OBSS based on information indicating the BSS Color of the OBSS included in the physical (PHY) layer preamble of the received frame. A communication device as described in item 5, characterized by the features described herein. (Item 7) The identification means identifies the received frame as the wireless frame communicated in the OBSS based on information indicating the BSS Identifier (BSSID) of the OBSS contained in the Medium Access Control (MAC) header of the received frame. A communication device as described in item 5, characterized by the features described herein. (Item 8) The system further includes a determination means for determining whether the received frame was transmitted from the access point or the non-access point station. A communication device as described in any one of items 1 to 7, characterized by the features described in item 1 to 7. (Item 9) The determination means determines that the received frame was transmitted from the access point based on the fact that the physical (PHY) layer preamble of the received frame contains information indicating that the received frame is a wireless frame in the downlink direction from the access point to the non-access point station. A communication device as described in item 8, characterized by the features described above. (Item 10) The determination means determines that the received frame was transmitted from the non-access point station based on the fact that the physical (PHY) layer preamble of the received frame contains information indicating that the received frame is a wireless frame in the uplink direction from the non-access point station to the access point. A communication device as described in item 8, characterized by the features described above. (Item 11) The determination means determines that the received frame was sent from the access point based on the fact that the field indicating the source of the received frame in the Medium Access Control (MAC) header of the received frame contains information indicating the MAC address of the access point. A communication device as described in item 8, characterized by the features described above. (Item 12) The determination means determines that the received frame was transmitted from the non-access point station based on the fact that the field indicating the destination of the received frame in the Medium Access Control (MAC) header of the received frame contains information indicating the MAC address of the access point. A communication device as described in item 8, characterized by the features described above. (Item 13) The determination means determines that the received frame was transmitted from the access point based on the fact that the Medium Access Control (MAC) header of the received frame contains information indicating that the received frame is the wireless frame output from the Distribution System. A communication device as described in item 8, characterized by the features described above. (Item 14) The determination means determines that the received frame was transmitted from the non-access point station based on the fact that the Medium Access Control (MAC) header of the received frame contains information indicating that the received frame is the wireless frame destined for the Distribution System. A communication device as described in item 8, characterized by the features described above. (Item 15) If the received frame is a wireless frame transmitted in an OBSS that is not detected by at least one of the communication device and the other communication device, the communication means will communicate using the first communication method instead of the second communication method. A communication device as described in any one of items 1 to 14, characterized by the features described in item 1 to 14. (Item 16) A communication method performed by a communication device that communicates with other communication devices using wireless frames compliant with the IEEE 802.11 standard series, A first communication method configured to enable communication by bonding a first channel and a second channel different from the first channel, comprising a communication process using a plurality of communication methods including: a first communication method that acquires transmission rights and performs communication using the first channel, and a second communication method that acquires transmission rights and performs communication using the second channel when the first channel cannot be used, An Overlapping Basic Service Set (OBSS) comprising the aforementioned communication device and an access point different from the other communication device, comprising a determination step of determining the OBSS in which the wireless frame transmitted by the access point is received by both the communication device and the other communication device on the first channel, The communication step is performed when the received frame received in the first channel after the identification is the radio frame communicated in the identified OBSS, Based on the fact that the received frame was transmitted from the access point, communication is performed using the second communication method. Based on the fact that the received frame was transmitted from a non-access point station other than the access point, communication is performed using the first communication method instead of the second communication method. A communication method characterized by the following features. (Item 17) A program to cause a computer to function as one of the means of a communication device described in any one of items 1 through 15.

[0070] The invention is not limited to the embodiments described above, and various modifications and variations are possible without departing from the spirit and scope of the invention. Accordingly, claims are attached to disclose the scope of the invention. [Explanation of Symbols]

[0071] 101:AP, 102:AP, 103:AP, 111:STA, 112:STA, 113:STA, 114:STA, 121:Network, 122:Network, 123:Network

Claims

1. A communication device that communicates with other communication devices using wireless frames compliant with the IEEE 802.11 standard series, A first communication method configured to enable communication by bonding a first channel and a second channel different from the first channel, comprising: a first communication method that acquires transmission rights and performs communication using the first channel; and a second communication method that acquires transmission rights and performs communication using the second channel when the first channel cannot be used; and a communication means that performs communication using a plurality of communication methods. An Overlapping Basic Service Set (OBSS) comprising the aforementioned communication device and an access point different from the other communication devices, comprising identification means for identifying the OBSS in which the wireless frame transmitted by the access point is received by both the communication device and the other communication devices on the first channel, The communication means, when the received frame received on the first channel after the identification is the wireless frame communicated in the identified OBSS, Based on the fact that the received frame was transmitted from the access point, communication is performed using the second communication method. Based on the fact that the received frame was transmitted from a non-access point station other than the access point, communication is performed using the first communication method instead of the second communication method. A communication device characterized by the following features.

2. The aforementioned specifying means is, A detection means for detecting OBSS in the first channel, The system includes an acquisition means for acquiring specific information indicating the OBSS detected in the first channel by the other communication device from the other communication device, Based on the OBSS detected by the detection means and the OBSS indicated by the identification information, the identification of the OBSS is performed. The communication device according to feature 1.

3. The identification means further includes a notification means for notifying the other communication device of the identification information indicating the OBSS detected by the detection means. The communication device according to feature 2.

4. The notification means maintains information indicating the OBSS detected in the first channel and makes the notification based on the detection of a new OBSS not included in the information, or the discontinuation of detection of OBSS included in the information. The communication device according to feature 3.

5. The system further includes identification means for identifying that the received frame is the wireless frame communicated in the OBSS. The communication device according to feature 1.

6. The identification means identifies that the received frame is the wireless frame communicated in the OBSS, based on information indicating the BSS Color of the OBSS included in the physical (PHY) layer preamble of the received frame. The communication device according to feature 5.

7. The identification means identifies that the received frame is the wireless frame communicated in the Obss based on information indicating the Obsss Identifier (BSSID) of the Obsss included in the Medium Access Control (MAC) header of the received frame. The communication device according to feature 5.

8. The system further includes a determination means for determining whether the received frame was transmitted from the access point or the non-access point station. The communication device according to feature 1.

9. The determination means determines that the received frame was transmitted from the access point based on the fact that the physical (PHY) layer preamble of the received frame contains information indicating that the received frame is a wireless frame in the downlink direction from the access point to the non-access point station. The communication device according to feature 8.

10. The determination means determines that the received frame was transmitted from the non-access point station based on the fact that the physical (PHY) layer preamble of the received frame contains information indicating that the received frame is a wireless frame in the uplink direction from the non-access point station to the access point. The communication device according to feature 8.

11. The determination means determines that the received frame was transmitted from the access point based on the fact that the field indicating the source of the received frame in the Medium Access Control (MAC) header of the received frame contains information indicating the MAC address of the access point. The communication device according to feature 8.

12. The determination means determines that the received frame was transmitted from the non-access point station based on the fact that the field indicating the destination of the received frame in the Medium Access Control (MAC) header of the received frame contains information indicating the MAC address of the access point. The communication device according to feature 8.

13. The determination means determines that the received frame was transmitted from the access point based on the fact that the Medium Access Control (MAC) header of the received frame contains information indicating that the received frame is the wireless frame output from the Distribution System. The communication device according to feature 8.

14. The determination means determines that the received frame was transmitted from the non-access point station based on the fact that the Medium Access Control (MAC) header of the received frame contains information indicating that the received frame is the wireless frame destined for the Distribution System. The communication device according to feature 8.

15. If the received frame is a wireless frame communicated in an OBSS that is not detected by at least one of the communication device and the other communication device, the communication means will communicate using the first communication method instead of the second communication method. The communication device according to feature 1.

16. A communication method performed by a communication device that communicates with other communication devices using wireless frames compliant with the IEEE 802.11 standard series, A first communication method configured to enable communication by bonding a first channel and a second channel different from the first channel, comprising a first communication method that acquires transmission rights and performs communication using the first channel, and a second communication method that acquires transmission rights and performs communication using the second channel when the first channel cannot be used, comprising a communication process using a plurality of communication methods, An Overlapping Basic Service Set (OBSS) comprising the aforementioned communication device and an access point different from the other communication devices, comprising a determination step of determining the OBSS in which the wireless frame transmitted by the access point is received by both the communication device and the other communication devices on the first channel, The communication process is performed when the received frame received on the first channel after the identification is the wireless frame communicated in the identified OBSS, Based on the fact that the received frame was transmitted from the access point, communication is performed using the second communication method. Based on the fact that the received frame was transmitted from a non-access point station other than the access point, communication is performed using the first communication method instead of the second communication method. A communication method characterized by the following features.

17. A program for causing a computer to function as each of the means of the communication device described in claim 1.

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